本節(jié)，直接寫通過(guò)代碼來(lái)學(xué)習(xí)。這些基本操作都比較簡(jiǎn)單，與這些基本操作相關(guān)的內(nèi)容在之前的1至6節(jié)基本介紹完畢。l 增加： 方法1：使用AddToXXX(xxx)方法：實(shí)例代碼如下：using (var edm = new NorthwindEntities()){Customers c = new Customers { CustomerID = "c#", City = "成都市", Address = "中國(guó)四川省", CompanyName = "cnblogs", Country = "中國(guó)", Fax = "10086", Phone = "1008611", PostalCode = "610000", Region = "天府廣場(chǎng)", ContactName = "風(fēng)車車.Net" };edm.AddToCustomers(c);int result = edm.SaveChanges();Assert.AreEqual(result, 1);Customers addc = edm.Customers.FirstOrDefault(cc => cc.CustomerID == "c#");Console.WriteLine("CustomerId={0},City={1}", addc.CustomerID, addc.City);}方法2：使用ObjectContext的AddObject(string entitySetName, object entity)方法。實(shí)例代碼如下：using (var edm = new NorthwindEntities()){Customers c = new Customers { CustomerID = "c2", City = "成都市2", Address = "中國(guó)四川省2", CompanyName = "cnblogs", Country = "中國(guó)", Fax = "10086", Phone = "1008611", PostalCode = "610000", Region = "天府廣場(chǎng)", ContactName = "風(fēng)車車.Net" };edm.AddObject("Customers", c);int result = edm.SaveChanges();Assert.AreEqual(result, 1);Customers addc = edm.Customers.FirstOrDefault(cc => cc.CustomerID == "c2");Console.WriteLine("CustomerId={0},City={1}", addc.CustomerID, addc.City);}其中，在代碼中，需要注意的是：AddObject方法中參數(shù)“entitySetName ”就是指對(duì)應(yīng)實(shí)體名稱，應(yīng)該是：“Customers”，而不是“NorthwindEntities.Customers”；l 更新： using (var edm = new NorthwindEntities()){Customers addc = edm.Customers.FirstOrDefault(cc => cc.CustomerID == "c2");addc.City = "CD";addc.ContactName = "cnblogs";addc.Country = "CN";int result = edm.SaveChanges();Assert.AreEqual(result, 1);Customers updatec = edm.Customers.FirstOrDefault(cc => cc.CustomerID == "c2");Console.WriteLine("CustomerId={0},City={1}", updatec.CustomerID, updatec.City);}其中，需要注意的是：不能去更新主鍵，否則會(huì)報(bào)“System.InvalidOperationException : 屬性“xxx”是對(duì)象的鍵信息的一部分，不能修改。”l 刪除： 實(shí)例代碼如下：using (var edm = new NorthwindEntities()){Customers deletec = edm.Customers.FirstOrDefault(cc => cc.CustomerID == "c2");edm.DeleteObject(deletec);int result = edm.SaveChanges();Assert.AreEqual(result, 1);Customers c = edm.Customers.FirstOrDefault(cc => cc.CustomerID == "c2");Assert.AreEqual(c, null);}l 事務(wù)： 實(shí)例代碼如下：NorthwindEntities edm = null;System.Data.Common.DbTransaction tran = null;try{edm = new NorthwindEntities();edm.Connection.Open();tran = edm.Connection.BeginTransaction();Customers cst = edm.Customers.FirstOrDefault(cc => cc.CustomerID == "c#");cst.Country = "CN";cst.City = "CD";edm.SaveChanges();tran.Commit();}catch (Exception ex){if (tran != null)tran.Rollback();throw ex;}finally{if (edm != null && edm.Connection.State != System.Data.ConnectionState.Closed)edm.Connection.Close();}至此，初級(jí)篇基本介紹完畢。后面，打算寫點(diǎn)，中級(jí)篇的東西。

　　

轉(zhuǎn)載于:https://www.cnblogs.com/Akgu/p/5156325.html

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